This invention relates to a railroad hopper car for shipment of a solid granular commodity and more particularly to a railroad hopper car having an effective hopper discharge outlet system for emptying a solid commodity from the railroad hopper car.
A common type of railroad freight car used today is the covered freight car of the type wherein a load is discharged through a discharge outlet on the underside of the body of the car. This type of railroad car, known also as a railroad hopper car, is commonly used to haul dry granular solids of various particle sizes such as grain, phosphates, plastics, and other dry bulk commodities that require protection from the natural elements.
It is well known in the prior art to provide for pneumatic discharge arrangements for hoppers of railroad cars, for example, as described in U.S. Pat. No. 3,246,805 and for example, a pneumatic discharge assembly in combination with a sliding gate or valve member as described in U.S. Pat. No. 4,388,026. The discharge hoppers located at the underside of the railroad cars are known to operate by pneumatic hoses connected to outlets positioned at two sides of a hopper compartment and an external detachable motor.
One problem encountered with such conventional pneumatic conveying systems is the tendency of product particulate material to form agglomerates and then the agglomerated product readily obstructing the discharge outlets. The problem of plugging of pneumatic outlets in the hopper compartments by agglomerated product is a serious problem particularly in the chemical industry.
During the discharge of the hopper cars, large chunks of the agglomerated product falls down to the hopper and "blinds off" the pneumatic outlets so that continuous off loading can not take place. "Bridging" of the material is also a problem. Agglomeration of product material may be caused by many factors including moisture, heat, time, the action caused by the weight of the material and compaction of the material during charging and moving of the railroad hopper car.
It is the aforementioned plugging problems that is desired to be solved.